The final level of 2013 federal transportation won’t be decided until November or December.

Congress passed a six-month funding bill and ensured 2013 transportation funding will be slightly lower than authorized by MAP-21. But that level is slightly higher than the 2012 level. Update: Transportation Weekly is reporting that “The federal-aid highway program will receive a flat freeze (no 0.612 percent bump, due to a combination of errors in the MAP-21 law and the Appropriations Committees’ attempt to correct those errors in the CR).”

Transportation interests are hopeful the higher funding level will be restored when Congress takes up budget issues in the November-December lame duck session. Of course there is still the issue of further automatic budget cuts to deal with (see our story, “Details of Possible $1.5 Billion Funding Cut to Roads, Transit and Rail“).

Congress has now left D.C. and will resume legislative business after the election. “It’s the earliest pre-election exit by Congress from Washington since 1960” according to the Christian Science Monitor.

The Senate passed the  bill 62-30 to fund the federal government from October 1 through March 27, 2013. The House had already passed the bill by a 329-91 margin; those 91 votes against the spending bill came from conservative Republicans, moderate Democrats, and from some liberal Democrats who believed the funding level was too low.

The funding level is about 0.6% higher than 2012 level. That’s the level approved in last year’s debt-limit level, and the level demanded by Democrats.  Republicans preferred a slightly lower funding level, but agreed in order to delay spending decisions. Each party believes voters will essentially side with them in the November elections, strengthening their position during the lame duck budget negotiations. For more on that see the Roll Call story “Voters Will Likely Resolve Fiscal Cliff.”

While the bill goes through March 27 most observers expect a complete-year funding bill will be hammered out in the post-election lame duck session. And that’s when we’ll learn if Congress will fund transportation at the slightly higher MAP-21 level or the lower 2013 level.

Congress’ approval rating of 13% is lowest ever for an election year, and its output so far is about half that of a typical Congress, according to the Christian Science Monitor.